Without limiting the scope of the invention, its background is described in connection with hydraulic fracturing to enhance production of trapped hydrocarbons. Conventional fracture designs focus on the creation of a fracture of desirable length, height and width. It is also desirable to increase fluid efficiency to reduce the amount of fluid to be used and to minimize damage to the proppant pack in the fracture. Such considerations typically lead to a fracture design using a reasonably high pump rate and as low a viscosity of the fracturing fluid as possible given the viscosity requirement for the desired fracture size.
In recent years, new fracturing designs and techniques have been developed to enhance production of trapped hydrocarbons. The new techniques focus on reducing stress contrast during fracture propagation while enhancing far field complexity and maximizing the stimulated reservoir volume.
For example, U.S. Pat. No. 8,210,257, incorporated herein by reference, entitled “Fracturing a stress-altered subterranean formation” discloses a wellbore in a subterranean formation includes a signaling subsystem communicably coupled to injection tools installed in the wellbore. Each injection tool controls a flow of fluid into an interval of the formation based on a state of the injection tool. Stresses in the subterranean formation are altered by creating fractures in the formation. Control signals are sent from the wellbore surface through the signaling subsystem to the injection tools to modify the states of one or more of the injection tools. Fluid is injected into the stress-altered subterranean formation through the injection tools to create a fracture network in the subterranean formation. In some implementations, the state of each injection tool can be selectively and repeatedly manipulated based on signals transmitted from the wellbore surface. In some implementations, stresses are modified and/or the fracture network is created along a substantial portion and/or the entire length of a horizontal wellbore.
Still another example includes U.S. patent application Publication Number US 2011/0017458, incorporated herein by reference, which discloses a method of inducing fracture complexity within a fracturing interval of a subterranean formation comprising characterizing the subterranean formation, defining a stress anisotropy altering dimension, providing a wellbore servicing apparatus configured to alter the stress anisotropy of the fracturing interval of the subterranean formation, altering the stress anisotropy within the fracturing interval, and introducing a fracture in the fracturing interval in which the stress anisotropy has been altered. A method of servicing a subterranean formation comprising the steps of introducing a fracture into a first fracturing interval, and introducing a fracture into a third fracturing interval, wherein the first fracturing interval and the third fracturing interval are substantially adjacent to a second fracturing interval in which the stress anisotropy is to be altered.
Still another example includes U.S. patent application Publication Number US 2004/0023816, incorporated herein by reference, which discloses a hydraulic fracturing treatment to increase productivity of subterranean hydrocarbon bearing formation, a hydraulic fracturing additive including a dry mixture of water soluble crosslinkable polymer, a crosslinking agent, and a filter aid which is preferably diatomaceous earth. The method of forming a hydraulic fracturing fluid includes contacting the additive with water or an aqueous solution, with a method of hydraulically fracturing the formation further including the step of injecting the fluid into the wellbore.